import java.util.ArrayList;

public class Test {
    public static void main(String[] args) {
        ArrayList<Integer>  list = new ArrayList<>();//没有分配空间
        String s1 = "welcome to bit";
        String s2 = "come";

        for (int i = 0; i < s1.length(); i++) {
            char ch = s1.charAt(i);
            if(!s2.contains(ch + " ")) {
                list.add(ch);
            }
        }
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }
        //arrayList.add(1);

    }

}
